Currently, the starting substrates and superstrates in many thin film photovoltaic (TFPV) solar cells are made of planer low iron (Fe) float glass on which a transparent conducting oxide (TCO) film is deposited. The TCO film is used to electrically contact one terminal of the TFPV solar cell. Although the planar TCO coated glass does an adequate job in allowing light to enter the cell, it does a poor job in light trapping. One method being employed today to improve light trapping is to texture the TCO film itself. In order to texture the TCO film it needs to be etched. Conventional wet etchants include traditional acids such as hydrochloric acid (HCl), sulfuric acid (H2SO4), and nitric acid. The etchant may also be a base such as potassium hydroxide, sodium hydroxide, or aluminum hydroxide. In the prior art, a method that produces a textured doped ZnO film consists of wet chemical etching with common acids such as diluted hydrochloric acid (HCl). Other acids that have been reported include sulfuric acid (H2SO4), nitric acid (HNO3), formic acid (HCOOH), and acetic acid (CH3COOH). In general, a simple chemical etch using 0.5 weight % HCl at room temperature for time duration of 15-45 seconds has been found to produce a surface texture on a TCO. But, many of these wet etchants are not ideal because the ability to control the texture along with the etch rate is a challenge. Additionally, many of these wet etchants are not environmentally friendly.